Scott said:
I misled you when I suggested it was a message. What happened is that
when I looked at Samsung Magician it showed (1) AHCI activated and (2)
SATA 2 only (no SATA 3).
I suspect the difference is of no importance for me, but I just
wondered if getting SATA 3 involves a new motherboard or can the
controller be replaced?
Thanks again for your help. It was you who encouraged me to proceed
when others (not here) suggested I should leave well alone!
For hard drives, it makes no difference. Yes, bursting data to the
small cache RAM on the hard drive controller board, works faster
at SATA III rates. But when it comes to sustained transfers (doing a
backup), the transfer is limited by the speed of the head to disk
platter interface.
With an SSD, it's different. Some of those can do 500MB/sec over SATA III
on a continuous basis. And if you wanted to impress your friends, you'd
get an add-in card to run that SSD. Getting only 200MB/sec using
some lesser flavor of SATA, wouldn't live up to the performance
billing of the SSD drive. (It would still feel fast, either way.)
The problem right now, is finding such a SATA III card that has good reviews.
I haven't been able to find a SATA III plug-in PCI Express card
with good reviews. For some people, they work, for others, nothing
but problems. Whether all the problems are "finger problems", I
don't know. I just consider it strange that at least one quality
product has not come along.
This is an example of an add-in card for a desktop computer.
The card is low-profile, meaning it fits in a "small" desktop.
This also comes with two faceplates, so the card can be
installed in a regular profile computer, or a low profile computer.
Dell has sold some desktops, where only low-profile cards fit.
This card also has an x4 PCI Express connector. You need to check
the motherboard, for a spare x4, x8, or x16 sized slot. This card
won't fit in an x1 slot, and I've selected a card like this on purpose.
It's to guarantee at least one SATA III port will run full rate
for you. I think this might be based on Marvell 9235, but in
any case, you'd definitely want to find a review site with
benchmarks, before buying it. The Marvell 9128 is limited to
300MB/sec, and we wouldn't want a repeat of that. Checking for
a benchmark for the card, is to avoid unpleasant surprises (i.e.
spend $50+, then find out it is no faster). To benchmark the
Marvell 9235 properly, someone has to combine it with a 500MB/sec
SSD for testing. Then run the RocketRaid in JBOD (meaning, even
a RAID card, can run single hard drives in a one-at-a-time mode).
http://www.newegg.com/Product/Product.aspx?Item=N82E16816115114
Not all desktop computers, have an excess of "good" add-in card slots.
A typical cheesy computer, has one x16 slot (for the video card), and
three x1 slots (for things like TV tuners). You'd want a machine with
two x16 slots, or x16 + x4, or some mixture of useful slots. And not
all computers (as is usual for the computing industry), are set up
for every possible addition.
This is one of the reasons, my current motherboard has two x16 slots.
I stick a mediocre video card in one slot, but the second slot
is available for "experiments", including projects like adding that
SATA III card.
As another example of the trickery involved, here is a motherboard
with two x16 slots. But the left-most large red slot, is actually
wired x4. So this system is actually x16 (white) plus x4 (red).
And the two x1 slots would be suited for TV tuners, or other
lower bandwidth stuff. You have to know the architecture fairly well,
look at the chips (check for bifurcation chips), to understand
what you're really getting. And a pre-build computer, they're
not likely to give you that nice, second, red slot for your
add-in SATA III card.
http://www.amazon.com/Biostar-LGA11...e=UTF8&qid=1363131927&sr=8-1&keywords=TZ77MXE
There's a lot of dishonesty in the computer industry. I was shocked,
shocked I tell you, to find out my 4GB/sec PCI Express slots, can't
even do 2GB/sec. Someone did a theoretical calculation, and
based on max packet size used in the design of my motherboard
chipset, determined it can't actually do 4GB/sec. I'm not
likely to run into a problem because of that, but if I
spend $1000 on an Areca RAID controller, I have to think
twice before I purchase it. Run of the mill "good" RAID
cards, can be limited by the IOP on the card, to around
800MB/sec. As I/O Processor chips improve, eventually
the cards become slot-limited (by crappy chipset designs
like the one my motherboard uses). And it only gets worse,
when the slots promise to have 8GB/sec or higher - you know
they can't possibly deliver those speeds in the real
world. Just waiting for someone to do the calc...
This is not a big deal. The point is, analysis needs to be
done, for any computer addition, to understand what is
possible - or why, the thing you purchased, didn't pan out.
We're still waiting for an explanation of why the Marvell
9128 only does 300MB/sec. Don't know why, about that one.
There have been a few driver releases for that one, too.
You catch issues like that, by finding a benchmark review
that was done using a 500MB/sec SSD. If someone uses
a 200MB/sec SSD to test a 500MB/sec RAID card, you learn
nothing that way. Many reviewers don't sweat the details
when they review. That's what makes it hard to find
good review info.
Paul
